Question

Chemical reaction may proceed with evolution or absorption of heat give one example of each

Answer 1

Answer:

Some chemical reactions may be either exothermic or endothermic in nature.

In endothermic reactions, a substance absorbs energy in the form of heat and undergoes a chemical reaction. An example is the heat energy absorbed during a chemical change involved in cooking, like baking a cake.

In exothermic reactions, heat energy is released. Explosion of fireworks is an example of exothermic chemical change. The explosion releases energy in the form of light.

Answer 2

Example of Endothermic Reaction: Reaction of barium hydroxide and ammonium chloride. Ba(OH)2 + 2NH4Cl2 →  NH4OH + BaCl2

Example of Exothermic Reaction: Combustion of methane which can be represented as : CH4 + O2 → CO2 + H2O + Heat